1. Field of the Invention
The present invention relates to a radiation imaging control apparatus, a radiation imaging system and a radiation imaging apparatus, and a method for controlling the same.
2. Description of the Related Art
In the field of digital radiation imaging apparatuses, large-area flat panel type sensors have been widely used as equal-magnification optical systems that use a photoelectric conversion device instead of an image intensifier for the purpose of improving resolution, reducing the volume, and preventing an image from being distorted.
Imaging apparatuses using the photoelectric conversion device include an amorphous silicon type imaging apparatus, a charge coupled device (CCD) type imaging apparatus, and a complementary metal-oxide semiconductor (CMOS) type imaging apparatus. An imaging apparatus having a large imaging area size can be easily manufactured by employing an image sensor that uses an amorphous silicon semiconductor on a glass substrate. However, on the other hand, the amorphous silicon semiconductor does not have a sufficient semiconductor characteristic for the operation due to, for example, a difficulty of microfabricating the semiconductor substrate on the glass substrate compared to a single-crystal silicon semiconductor substrate, resulting in an increase in the capacity of an output signal line. The CCD type imaging apparatus is a complete depletion type and is highly sensitive, but is unsuitable for increasing an imaging area size because, for example, this imaging apparatus leads to an increase in the number of transmission stages for charge transmission as an imaging apparatus having a large imaging area size, and requires power consumption more than ten times compared to the CMOS type imaging apparatus.
US Unexamined Patent Application Publication NO. 2002/0190215 discusses a large-area flat panel type sensor using a CMOS type image sensor as a photoelectric conversion device. This sensor realizes a large area size by tiling rectangular semiconductor substrates, each of which is formed by cutting out a CMOS type photoelectric conversion device from a silicon semiconductor wafer into a rectangular shape. Due to microfabrication, the CMOS type image sensor allows data to be read out at a higher speed than the amorphous silicon type image sensor, and further, provides high sensitivity. Further, the CMOS type image sensor has no problem in the number of transmission stages for charge transmission and power consumption unlike the CCD type image sensor, thereby easily realizing a large imaging area size. It is known that the CMOS type image sensor is highly advantageous as a large-area flat panel type sensor, especially as a moving image capturing apparatus.
The state of an imaging apparatus shifts based on, for example, command communication from a command communication control apparatus to the imaging apparatus. Further, similarly, an imaging mode is also set based on command communication from the command communication control apparatus to the imaging apparatus. Then, the imaging apparatus becomes ready for an imaging operation through these respective processes of command communication.
However, execution of these respective processes of command communication requires a user to perform several operations on an operation panel, which raises a problem of the inability to deal with a sudden imaging request. Further, there is such a problem that desired command communication cannot be performed and therefore imaging is impossible, for example, when the command communication control apparatus is not started up or has gone down.